Don't repeat yourself (DRY)

Try to observe the DRY principle.

Do your absolute best to avoid duplicate code. Duplicate code is bad because it means that there's more than one place to alter something if you need to change some logic.

Imagine if you run a restaurant and you keep track of your inventory: all your tomatoes, onions, garlic, spices, etc. If you have multiple lists that you keep this on, then all have to be updated when you serve a dish with tomatoes in them. If you only have one list, there's only one place to update!

Often you have duplicate code because you have two or more slightly different things, that share a lot in common, but their differences force you to have two or more separate functions that do much of the same things. Removing duplicate code means creating an abstraction that can handle this set of different things with just one function/module/class.

Getting the abstraction right is critical. Bad abstractions can be worse than duplicate code, so be careful! Having said this, if you can make a good abstraction, do it! Don't repeat yourself, otherwise you'll find yourself updating multiple places any time you want to change one thing.

Bad:

from typing import List, Dict
from dataclasses import dataclass


@dataclass
class Developer:
    def __init__(self, experience: float, github_link: str) -> None:
        self._experience = experience
        self._github_link = github_link

    @property
    def experience(self) -> float:
        return self._experience

    @property
    def github_link(self) -> str:
        return self._github_link


@dataclass
class Manager:
    def __init__(self, experience: float, github_link: str) -> None:
        self._experience = experience
        self._github_link = github_link

    @property
    def experience(self) -> float:
        return self._experience

    @property
    def github_link(self) -> str:
        return self._github_link


def get_developer_list(developers: List[Developer]) -> List[Dict]:
    developers_list = []
    for developer in developers:
        developers_list.append({
            'experience': developer.experience,
            'github_link': developer.github_link
        })
    return developers_list


def get_manager_list(managers: List[Manager]) -> List[Dict]:
    managers_list = []
    for manager in managers:
        managers_list.append({
            'experience': manager.experience,
            'github_link': manager.github_link
        })
    return managers_list


## create list objects of developers
company_developers = [
    Developer(experience=2.5, github_link='https://github.com/1'),
    Developer(experience=1.5, github_link='https://github.com/2')
]
company_developers_list = get_developer_list(developers=company_developers)

## create list objects of managers
company_managers = [
    Manager(experience=4.5, github_link='https://github.com/3'),
    Manager(experience=5.7, github_link='https://github.com/4')
]
company_managers_list = get_manager_list(managers=company_managers)

Good:

from typing import List, Dict
from dataclasses import dataclass


@dataclass
class Employee:
    def __init__(self, experience: float, github_link: str) -> None:
        self._experience = experience
        self._github_link = github_link

    @property
    def experience(self) -> float:
        return self._experience

    @property
    def github_link(self) -> str:
        return self._github_link


def get_employee_list(employees: List[Employee]) -> List[Dict]:
    employees_list = []
    for employee in employees:
        employees_list.append({
            'experience': employee.experience,
            'github_link': employee.github_link
        })
    return employees_list


## create list objects of developers
company_developers = [
    Employee(experience=2.5, github_link='https://github.com/1'),
    Employee(experience=1.5, github_link='https://github.com/2')
]
company_developers_list = get_employee_list(employees=company_developers)

## create list objects of managers
company_managers = [
    Employee(experience=4.5, github_link='https://github.com/3'),
    Employee(experience=5.7, github_link='https://github.com/4')
]
company_managers_list = get_employee_list(employees=company_managers)

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